1. Field of the Invention
The present invention generally relates to chip packaging techniques and modules. More particularly, the present invention relates to wire-free chip modules and methods that are suitable for use in a wide variety of applications, including a power module having relatively high current density and efficiency, as well as relatively low parasitic inductance.
2. Background Art
System on chip (SOC) packaging techniques are well-known and has been used in power supply applications. In recent years, several semiconductor manufacturers have released power modules in SOC packaging form. For example, as shown in FIG. 1 and FIGS. 2A-2B, a semiconductor power circuit 98 may comprise an integrated circuit (IC) 101 and at least one passive component, such as inductor 102. Traditional SOC techniques that include assembling semiconductor power circuit 98 into a SOC power module 100 by using surface mounted topologies for its components and by mounting these components, such as an IC 101 and inductor 102, to a printed circuit board (PCB) or equivalent substrate 103 having conductive traces 104 and vias 107. IC 101 is in the form of a power IC and includes a pair of switching devices, M1 and M2, that are coupled together in series at a connection point, named “switch connection point”, 108 as shown. This SOC technique also includes using wire bonds 106 to interconnect these components through their respective solder pads 105 to conductive traces 104. While this technique is mature and more readily available in the industry, it suffers from at least one of the following disadvantages: relatively high manufacturing cost, higher power loss in the interconnections, relatively large parasitic inductance, current capability limited by the use of the wire bonds and PCB technique, and a package size that has a relatively large footprint and low thermal dissipation. These drawbacks limit the suitability of using SOC packaging to semiconductor power circuits that use relatively low current, low switching frequency or both. Consequently, a need exists for a solution that minimizes or eliminates most, if not all of the above problems.